Why most ‘waterproof’ running jackets still leave you soaked

You’d think a waterproof running jacket would be a must-have for tackling the elements during training. Not always.

For year-round outdoor runners, a waterproof layer should offer solid protection from the rain. But in reality, many so-called waterproof running jackets fall short, leaving you soaked and miserable. 

We’ve all been there, caught in a downpour mid-run, relying on a jacket that promised to be waterproof only to become soaked in minutes. I often find myself wondering – is this jacket truly waterproof? It claims to be, but becomes wet through almost instantly and water seeps through the seams. 

When I buy running gear, I want to invest in durable kit that holds up to real-world conditions. Otherwise, what’s the point?

But finding a running jacket that truly delivers is no small task. It needs to be lightweight, breathable, agile, and most importantly, genuinely waterproof. If it sounds like a tall order, that’s because it is. 

That’s why I want to dig deeper into what “waterproof” really means in the context of running jackets and what credentials to look for if you want gear that can actually handle the rain. 

What “waterproof” really means 

When choosing a waterproof running jacket, you’ll often see a measurement called hydrostatic head (HH) which is the standard way of measuring how waterproof a fabric is. 

It refers to how high a column of water (in millimetres) a fabric can withstand before it starts to leak. For example, a jacket rated at 10,000mm means it can hold back a 10m column of water before moisture begins to seep through. 

The higher the number, the more waterproof the fabric is, at least in theory.

However, real-world use isn’t as simple as lab tests. Pressure from wind, movement, and a running pack can significantly reduce a fabric’s resistance to water. Hence why some runners find that even jackets with high hydrostatic head ratings still let in water. 

For most, a rating of 10,000–20,000 mm HH strikes a good balance between waterproofing and breathability. Just remember that waterproof doesn’t always mean invincible, especially in heavy rain or long efforts.

Other jacket features that are important to look out for to create a fully waterproof later include things like bonded or taped seams to stop moisture seeping through, an internal storm flap behind the zipper to block out wind and water, elasticated or adjustable hems and sleeves, and a decent hood with peaked tip for shelter.

Do you have to just sweat it out? 

As mentioned above, to be truly waterproof, a jacket needs to strike a balance with breathability. Since waterproofing typically involves a membrane or coating to seal out (or in) moisture, this often leads to the most waterproof options being the least able to expel sweat. 

And what’s the point in keeping out the rain if you’re swimming in sweat under a jacket? So, is there no way to have both a highly waterproof and adequately breathable layer? 

Typically, there’s always going to be a trade-off between the two. Most waterproof membranes have microscopic pores that should be small enough to block liquid from passing through the material, but large enough to let out sweat in the form of water vapour.

As you can imagine, this is a fine balance. Common waterproofing technologies used include Gore-Tex and Pertex Shield. The best thing to do is opt for a jacket with the best tech and most high-quality, lightweight materials possible.  

Other waterproof jackets use a hydrophilic membrane to move moisture through the material without the use of pores. Instead, the fabric absorbs sweat and moves it outwards through the process of diffusion. 

Certain factors will put pressure on the breathability of your run layer, no matter the efficacy of the fabric. These include: high intensity efforts, high humidity environments, wearing non-breathable layers under the jacket, and a lack of in-jacket ventilation. 

Many running coats will have ventilation panels or slits in the form of pit zips, dowards facing vents so the rain slides off rather than in, and mesh liners. Though it’s easy to see a gap in material as perhaps a downfall to waterproofing, designs can be incredibly smart and you’ll be glad of the extra ventilation when in motion. 

The bottom line 

Essentially, there are many run jackets that fall short of their all-weather promises and many that perform brilliantly. This is where a expert running jacket reviews have make such a hige difference in sorting the wheat from the chaff. 

When shopping for your next running jacket, look for options that move with you as you run without that annoying rustle, are breathable enough to not feel like you’re sweating in a crisp packet, and have at least 15,000 HH waterproofing to make rainy weather adventures more enjoyable.